I just went through this with my dealer and Husqvarna US with my 701. You do not have to take the bike to the dealer in order to maintain your warranty.
Unfortunately, the first service reset needs to be done by the dealer on the computer. However, from there on out the process is as follows:
Press mode until Odometer Appears / THEN press Set until Service appears / THEN Press&Hold Set until “reset service interval” clears (Approx. 10 seconds)
I don’t know for sure about the 401, but on the 701 the repair manual doesn’t call for a valve adjustment until 6000mi, which was mildly surprising.